We already mentioned that the formation scenario proposed by [1]} supposed that FGs formed at high redshift, with few interactions with the large-scale structure along their lives. This would leave enough time for the M\(^*\)  galaxies to merge with the BCG, thus forming the \(\Delta m_{12}\)  gap. On the other hand, [2]} suggested the so-called failed group scenario, in which the BCG is formed as a local over density and no other bright galaxy formed within the group.
